Lime-nitrogen process and product



UNITED STATES PATENT OFFICE.

JOB MORTEN AUGUST STILLESEN, OF NIAGARA FALLS, NEW YORK.

LIME-NITROGEN PROCESS AND PRODUCT.

No Drawing. Application filed August 8, 1911, Serial No. 643,011.Renewed November 30, 1917.

Patented Aug. 2, 1921.

Serial To all whom it may concern:

Be it known that I, JOB MORTEN AUGUST STILLESEN, a subject of the Kin ofNorway, residing at Niagara Falls, in t e county of Niagara and State ofNew York, have invented certain new and useful Improvements inLime-Nitrogen Processes and Products, of which the following is a full,clear, and exact specification.

This invention relates to preparation of lime nitrogen, and moreparticularly has reference to improvements in the process of producinglime nitrogen broadly described in my Patent No. 982,311, dated January24, 1911. The present invention also comprises the product resultingfrom my process.

In further experimentation, I have dis covered that the obj ectionablequalities given to lime nitrogen by the presence of free lime (CaO)therein are overcome equally as well for many purposes, if the free limebe only changed into basiccarbonates of calcium, of which a number areknown, such as CaCO,. CaO or 2CaCO .CaO, and that lime nitro gencontaining basic carbonates of calcium will have a greater percentage ofcombined nitrogen per unit of weight than has heretofore been obtained.

It has been found that some soils require lime, while others do not, andit is therefore desirable, in the manufacture of llme nitrogen oranalogous nitrogen bearing fertilizer materials, to be able to regulateat will the contents of free or combined lime. Thereby, it is possible,by my process of treating materials containing either free or hydratedlime, to obtain just the proper composition to secure the best resultswithout injuring the soil. This is effected, according to the presentinvention, by combining the free lime, or water treated lime, or bydrated lime containing material, with carbon dioxid according to thebasicity desired.

I have also discovered that by treating the lime containing materialwith water before treatment with carbon dioxid, the latter will beabsorbed quicker, and thereby the cost of producing lime nitrogencontaining either neutral or basic carbonates, or basic hydratedcarbonates, considerably reduced.

The reaction which occurs in the neutralization of lime to basic ornormal carbonates, with carbon dioxid, is an exothermic one,

and can take place at low temperatures with the evolution of much heat.I have now discovered that it is advantageous, in treatng the free orhydrated lime in lime nitrogen with carbon dioxid, to keep thetemperature of the reaction as low as possible in order to prevent thetemperature of the whole mass from rising too high, with consequentpossible decomposition of the lime nitrogen. To prevent excessive heatin this exothermic reaction, I propose to employ liquid or solid carbondioxid gas, or carbon dioxid gas under expansion, whereby the heatliberated by the reaction of carbon dioxid and lime will be absorbed bythe expansion of the carbon dioxid, and the temperature of the entireprocess thereby maintained as low as desired.

I have further discovered that one or the other of several basiccarbonates are formed 1n treating lime with carbon dioxid, in proportionas the gas is absorbed, that is, the process is a progressive oneprovided the supply of gas be maintained, normal carbonate beingproduced successively after the basic carbonates and after prolongedtreatment with the right proportion of carbon dioxid.

My invention therefore contemplates a process for producing limenitrogen containing basic carbonates by treatment with a deficiency ofcarbon dioxid, and the production of lime nitrogen containing normalcarbonate by treatment with an excess of carbon dioxid, whereby the timerequired is shortened, the cost of production decreased and productscontaining an increased precentageof fixed nitrogen obtained.

The invention also comprehends a product consisting of lime nitrogen andone or more basic carbonates of calcium, with or without normalcarbonates.

The process of obtaining lime nitrogen is substantially the same as thatdescribed in the patent above-referred to, wherein cal cium carbid istreated with nitrogen, in the usual manner. Such product contains aconsiderable percenta e of free lime, formed in the manufacture o thecarbid, and I will now describe specifically the process whereby Iproduce one or the other or all of the basic calcium carbonates abovereferred to or normal carbonate, directly from the free lime containingmaterial by treatment with solid or liquid carbon dioxid, or with carbondioxid gas under expansion.

According to one part of my invention, I propose to treat the free limecontaining material, such forexample as lime nitrogen, with a deficiencyof carbon dioxid until the first basic calcium carbonate (CaCO,.CaO) isformed, .then by further treatment this basic carbonate takes up morecarbon dioxid and goes over to a second basic carbonate (2CaCO .CaO)then to a third (3CaCO CaO), etc. While each of these compounds containslime (CaO) in combination, I have found that the injurious effect of thelatter in its free state is reduced in the basic compounds, and that theresultant lime nitrogen containing a basic carbonate can be used withthe same advantages as are attained by the normal carbonate, dependingupon the particular requirements.

I have also found it advantageous in carrying out my invention to firsttreat the mixture of lime nitrogen and lime, as received from the limenitrogen furnace, withjwater, or with water suflicient to slake the freelime present, whereby some or all of the lime may become hydratedaccording to the reaction:

When the water treated mixture of lime nitrogen and lime is treated atatemperature below that of dissociation of calcium carbonate (850900 C.)with carbon dioxid in a condition of expansion, whether gas, liquid orsolid, normal or basic carbonate of calcium and water will be formed, orbasic hydrated calcium carbonates may be formed according to thereaction:

or the water may be evaporated by the heat of the reaction:

The proportion of carbon dioxid to lime may vary from about 40% for thefirst basic carbonate, to about 60% for the second carbonate, to about80% or more for the normal carbonate, for ordinary raw lime ni-""trogen. To obtain basic hydrated carbonates more water will berequired, but it is not possible to give any precise proportions ofeither carbon dioxid or water for a given result, because the characterand composition of the raw materials which can be treated vary sogreatly.

In this specification where I refer to basic carbonates of calcium, Iintend to cover either or all of these carbonates of calcium, Whetherhydrated or not, other than the normal carbonate (CaCO The last featureof my improvements comprises specifically the treatment of a. limecontaining material, such as lime nitrogen with or without Water beingpresent, with solid or liquid carbon dioxid or with carbon dioxid gasunder expansion, either to produce basic, or basic hydrated or normalcarbonate of'calcium. Carbon dioxid is a gas at ordinary temperaturesbut when cooled to 17 C., and subjected to a pressure of about 54atmospheres, it liquefies. \Vhen the liquid is released from pressure,it evaporates at ordinary temperature, as does the solidified gas, whichcan be produced for instance, by pouring the liquid from one vessel intoanother. The evaporation of a part of the liquid while being pouredabsorbs so much heat that the remaining por tion solidifies into a whitesnow, 'which slowly expands in the air. According to my process, Ipropose to mechanically mix or to have the free lime containingmaterial, such as lime nitrogen, come into contact with liquid or solidcarbon dioxid, or with carbon dioxid gas under expansion, and thereaction immediately commences, the heat or part of the heat given offby the reaction being absorbed by the expansion of the carbon dioxid,and thereby the resultant temperature of the mass is maintained at thedesired degree, or low enough so that there will be no loss of nitrogenor ammonia.

While I have specifically referred to the treatment of lime nitrogencontaining free lime, I do not wish to be understood as limiting myselfhereto, since my discoveries are valuable and useful wherever it isdesired to remove free lime as an impurity from compositions or acaustic oxid which will combine with CO from such materials as would beinjured by excessive heat, as other nitrogen compounds of calcium andanalogous metals.

hat is claimed, is:

1. The process which consists in treating lime containing material withcarbon dioxid in a condition of simultaneous expansion and cooling.

2. The process which consists in treating lime containing material withcondensed carbon dioxid.

3. The process which consists in treating moistened lime containingmaterial with car- 115 bon dioxid in a condition of simultaneousexpansion and cooling.

4. The process which consists in treating moistened lime containingmaterial with condensed carbon dioxid.

5. The process which consists in treating lime nitrogen with water andwith carbon dioxid.

6. The process which consists in treating lime nitrogen with water andwith carbon 125 dioxid in a condition of simultaneous expansion andcooling.

7. In the process of modifying lime in a nitrogen carbon compound. thestep which consists in adding condensed carbon dioxid 130 and permittingit-to expand in intimate relation' therewith.

8.- The process of neutralizing lime .nitrogen consisting in moisteningand treating with condensed carbon dioxid.

9. The process of neutralizing lime nitro gen consisting inmoisteningand treating with condensed carbon dioxid in such manner as to producebasic carbonate of calcium.

10. The proces of neutralizing lime nitrogen consisting in moisteningand then treat- -mg with a proportion of condensed carbon dioxid such asto produce a predetermined basic carbonate of calcium.

11. The process-of neutralizing lime nitrogen consisting in moisteningand then treatmg with a proportion of condensed carbon dioxid such as toproduce a predetermined carbonate of calcium.

12. The process which consists in treating a lime containing materialwith water and carbon dioxid in such manner as to form basic carbonateof calcium.

13. The process which consists in treating a lime containing materialwith carbon dioxid at or below its temperature of evaporation.

14;. The process which consists in treating lime nitrogen and limecomposition with carbon dioxid at or below its temperature ofevaporation.

;15. The process which consists in treating a lime and lime nitrogencomposition with expanding carbon dioxid at a temperature materiallybelow 60 C.

16. The process which consists in treating lime nitrogen with water anda gas in a condition of simultaneous expansion and cooling to maintainthe temperature below that of decom osition of lime nitrogen.

v 17. he process of controlling the temperature of the reaction ofcarbon dioxid and an alkaline earth oxid consisting in expandingcondensed carbon dioxid mixed with the alkaline earth oxid.

18. The process of producing a predetermined carbonate of an alkalineearth metal consisting in expanding condensed carbon dioxid mixed inpredetermined proportion with the alkaline earth oxid of said metal.

19. A composition of matter comprising lime nitrogen and basic carbonateof calcium.

20. A composition of matter comprising lime nitrogen and a plurality ofbasic carbonates of calcium.

21. A composition of matter comprising lime nitrogen, normal carbonateof calcium, and a basic carbonate of calcium.

22. A composition of matter comprising lime nitrogen and such carbonateof calcium as is formed by the combination of lime with carbon dioxid ina condition of simultaneous ex ansion and cooling. 1

n testimony whereof I ailix my signature, in presence of two witnesses.

JOB MORTEN AUGUST STILLESEN.

Witnesses:

E. M. BENNETT, RUTH E. ELSHEIMER.

